Amplitude Modulation

Superimpose a low-frequency signal onto the amplitude of a high-frequency carrier and observe envelope changes

Real-World Applications

Medium wave (MW) radio stations (535-1605kHz) use amplitude modulation. Aviation radio communications (118-137MHz) also use AM because when two signals overlap, pilots can still hear the "beat tone" to realize someone else is speaking simultaneously, while FM would cause the "capture effect" making weaker signals disappear completely.

Experiment Steps

1. Observe Envelope: Waveform contour in time domain follows the modulation signal
2. Over-modulation: Envelope distortion occurs when m > 1
3. Spectrum Analysis: Carrier and sidebands fc ± fm

Simulation Experiment

Functions: models.phy.amModulate(), models.phy.generateSineMessage()